Abstract:

Objective To investigate the utility of dual?energy CT combined with musculoskeletal ultrasonography in differentiating between calcium pyrophosphate deposition disease and gouty arthritis. Methods A retrospective analysis was conducted on the medical records of 102 patients diagnosed with gouty arthritis and 102 patients diagnosed with calcium pyrophosphate deposition disease. These patients were categorized into the Gout group and Calcium Deposition group， respectively， based on their respective diagnoses. All patients underwent dual?energy CT and musculoskeletal ultrasonography examinations， while joint fluid aspiration results or intra?articular crystal material served as the gold standard for diagnosis. The diagnostic efficacy of dual?energy CT and musculoskeletal ultrasonography in discriminating between calcium pyrophosphate deposition disease and gouty arthritis was evaluated. Results In the gout group， the proportion of male patients and serum uric acid levels were significantly higher compared to those in the calcium deposition group （P < 0.05）. The prevalence rates of knee joint， first metatarsophalangeal joint， and ankle joint involvement were higher in the gout group， while knee joint， wrist joint， and shoulder joint involvement rates were higher in the calcium deposition group. The proportions of irregular bone cortex， cartilage injury， and degenerative meniscus changes were lower in the gout group compared to the calcium deposition group （P < 0.05）. The proportions of double contour sign， tophus formation， hyperechoic band within ligaments or tendons， and bone erosion were higher in the gout group compared to the calcium deposition group （P < 0.05）， whereas cartilage calcification was lower in the gout group （P < 0.05）. The sensitivities for diagnosing calcium pyrophosphate deposition disease and gouty arthritis using dual?energy CT scan alone， musculoskeletal ultrasound alone， and their combined use were 86.27%， 83.33%， and 94.12% respectively. The specificities for diagnosing these conditions using dual?energy CT scan alone，musculoskeletal ultrasound alone，and their combined use were 89.22%，88.24%， and 86.27% respectively. The positive predictive values were 88.89%， 87.63%， and 87.27%， respectively. The negative predictive values were 86.67%， 84.11%， and 93.63%， respectively. The accuracies were 87.75%， 85.78%， and 90.20% respectively. The agreement Kappa values were 0.755， 0.716， and 0.804 respectively. Conclusions The integration of dual?energy CT and musculoskeletal ultrasonography exhibits promising diagnostic efficacy in discriminating between calcium pyrophosphate deposition disease and gouty arthritis. This combined approach serves as a valuable adjunctive tool for the diagnosis of both conditions.

Key words: Calcium phosphate deposition disease, Gouty arthritis, Dual energy CT, Muscle bone ultrasound, diagnosis